Embodiments of the invention relate to cataract surgery, and more specifically, to objectively grading a cataract.
A cataract is a clouding that develops in the crystalline lens of the eye (or pupil) or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light. Surgical procedures may be used to remove cataracts. Grading of a cataract is performed prior to removal though. The importance of pre-operative grading allows for the pre-programming of cataract surgical equipment to ideally match a grade of the cataract to an appropriate energy setting and fluid setting to most efficiently remove the cataract.
Cataracts may be graded by visual inspection and assignment of numerical values to indicate severity. Grading systems currently known to evaluate a cataract are the Oxford Clinical Cataract Classification and Grading System, the Johns Hopkins system, and the Lens Opacity Classification System (LOCS, LOCS II, and LOCS III). In general, photographs of slit lamp cross-sections of the lens are used as references for grading nuclear opalescence and nuclear color, and photographs of the lens seen by retroillumination are used as references for grading cortical and posterior subcapsular cataract. More specifically, with respect to the LOCS III, cataracts are examined based on individual components, such as nuclear, cortical, and posterior sub capsular, in comparison to a series of photographic graded images printed on paper. A subjective comparison is then made between a patient's cataract to the photographic series to determine where the individual cataract would match against the photographic series so as to establish a graded number. Thus, the comparison is performed based on an examiner's perspective rather than a perspective that is replicable examiner to examiner.
Existing grading system relies on subjectivity, which the inventor believes is too subjective, with respect to grading cataracts. Because of the subjectivity which allows for varied interpretation, difficulties arise in comparing a particular density of a cataract and equating it to different surgical techniques and parameters in order to remove it.
Surgeons and surgical equipment manufacturers, such as but not limited to phacomulsification (“phaco”) technology manufacturers, and those with cataracts would benefit from a system and method that provided an objective grading of a cataract wherein the system and method are also reproducible for use at any location where cataracts are graded. Furthermore, such a reproducible system and method would be beneficial to allow for a better comparison between surgeons and surgical equipment manufacturers as to what generates the least amount of energy and fluid consumption inside the eye when comparing different cataract grades.